In ordinary automotive vehicles, only the front road wheels or the rear road wheels are steerable. Some vehicles such as those having exceptionally elongated wheel bases are two or more pairs of steerable road wheels. These pairs of steerable road wheels are coupled together either mechanically or through hydraulic circuits. One pair of steerable road wheels is steered by human intervention and another pair of steerable road wheels is steered through an angle proportional to the angle through which the former pair of road wheels is steered. A vehicle having such pairs of steerable road wheels is capable of being steered to make a sharp turn at a low speed where an ample space is not available for the turning movement of the vehicle.
When a vehicle of this type is making a turn, the vehicle is subject to not only yawing motion but also to lateral slip about a vertical axis which passes through the center of gravity of the vehicle. Due to the lateral slip thus involved in a turning motion of the vehicle, the vehicle is not capable of travelling in a direction tangential to the turning circle so that the vehicle driver is not enabled to have a correct control over the direction in which the vehicle is to advance.
Since, furthermore, the lateral acceleration of the vehicle as sensed by the vehicle driver is not in conformity to the acceleration of the centrifugal force acting on the vehicle making a turn, the vehicle driver is compelled to maneuver the vehicle with a strained sensation.
The present invention contemplates elimination of these drawbacks thus far encountered in a vehicle using two or more pairs of steerable road wheels.